1. Field of the Invention
This invention relates to a primary radiator which is a component element of an antenna to be mounted in an artificial satellite, and, more particularly to a structure of a primary radiator for preventing an electrical charge caused by charged particles and the like found in the environment of space.
2. Description of the Prior Art
Conventional self-independent primary radiators are typically constructed such that a cap-like sub-reflection part is fixed to an opening of an electrical supplying waveguide, with an insulator formed of resin material which permits good penetration of electromagnetic waves being used for fixing the sub-reflector. In such devices there has typically been no arrangement for providing DC conduction between the sub-reflector and the electrical supplying waveguide.
In a case where the above-described primary radiator is mounted in a satellite and used in space, since there is no DC conduction between the sub-reflector and the electrical supplying waveguide, charged particles tend to accumulate at the sub-reflector under a mutual action with plasma faced on an orbit of the satellite. Because of this, an electrical potential difference generated between both elements is increased to cause a discharged short circuit or some similar problem.
Such a discharged short circuit as above has some significant disadvantages in that it becomes a source of noise which can adversely affect the operation of the communication system in the satellite.